A solder or adhesive is used for mounting electronic components, such as semiconductors, on a printed wiring board of an electronic device, and for assembly of electronic components such as semiconductors.
In particular, electronic components formed of ceramics or the like cannot be directly soldered. Accordingly, a pad consisting of a plate coating is provided on the surface of a workpiece of an electronic component, and a solder bump is formed on the pad. After that, soldering is performed through the bump.
Heretofore, a method using a solder paste has often been used as a solder bump forming method. After a solder paste is applied onto a plate coating of a workpiece by a printer or a dispenser, the solder paste is melted by reflow heating to thereby form a bump. This method is a low-cost method. However, printing has limitations on the range of available printing materials, and it is difficult to form a bump corresponding to a fine circuit pattern.
A bump forming method using a solder ball is also known. A fine solder ball is mounted on a workpiece of an electronic component, and the solder ball is reflow-heated to thereby form a bump. This method makes it possible to form a bump corresponding to a fine circuit pattern. However, the cost of the solder ball itself is high, which causes an increase in the overall cost.
As a method for forming a bump corresponding to a fine circuit pattern at a low cost, a so-called molten solder method of forming a solder bump by discharging a molten solder has attracted attention. In the molten solder method, a solder deposition device is known in which a molten solder is efficiently supplied to a plurality of sections by scanning the molten solder in the horizontal direction from a nozzle opening of a container containing the molten solder (Japanese Patent Laid-Open No. 2-015698).
Further, a bump forming device including a mechanism in which after completing an operation, a nozzle head is cooled, and the nozzle head is raised to separate from a mask is known (WO2013/058299A).